Table 2.

Sensitivity values of $R_0$.

Parameters	$\Lambda$	${\beta }_1$	${\beta }_2$	${\beta }_3$	${\alpha }_1$	${\alpha }_2$	${\alpha }_3$	$\xi$	$\gamma$	${\delta }_1$	${\delta }_2$
Sign of sensitivity index of $R_0$	＋	＋	＋	＋	–	–	–	–	＋	–	–